OF THE CAMERA OBSCURA.
Before proceeding to a particular description of the different kinds
of telescopes, I shall first give a brief description of the Camera
Obscura, as the phenomena exhibited by this instrument tend to
illustrate the principle of a refracting telescope.
The term _Camera Obscura_ literally signifies a darkened vault or roof;
and hence it came to denote a chamber, or box, or any other place
made dark for the purpose of optical experiments. The camera obscura,
though a simple, is yet a very curious and noble contrivance; as it
naturally and clearly explains the manner in which vision is performed,
and the principle of the telescope, and entertains the spectator with
a most exquisite picture of surrounding objects, painted in the most
accurate proportions and colours by the hand of nature. The manner of
exhibiting the pictures of objects in a dark room is as follows:--In
one of the window-shutters of a room which commands a good prospect
of objects not very distant, a circular hole should be cut of four or
five inches diameter. In this hole an instrument should be placed,
called a _Scioptric ball_, which has three parts, a frame, a ball, and
a lens. The ball has a circular hole cut through the middle, in which
the lens is fixed, and its use is, to turn every way so as to take in
a view of objects on every side. The chamber should be made perfectly
dark; and a white screen, or a large sheet of elephant paper, should be
placed opposite to the lens, and in its focus, to receive the image.
If then, the objects without be strongly enlightened by the sun, there
will be a beautiful living picture of the scene delineated on the white
screen, where every object is beheld in its proportions, and with its
colours even more vivid than life; green objects appear in the picture
more intensely green, and yellow, blue, red or white flowers appear
much more beautiful in the picture than in nature; if the lens be a
good one, and the room perfectly dark, the perspective is seen in
perfection. The lights and shadows are not only perfectly just, but
also greatly heightened; and, what is peculiar to this delineation,
and which no other picture or painting can exhibit--the _motions_ of
all the objects are exactly expressed in the picture; the boughs of
the trees wave, the leaves quiver, the smoke ascends in a waving form,
the people walk, the children at their sports leap and run, the horse
and cart move along, the ships sail, the clouds soar and shift their
aspects, and all as natural as in the real objects; the motions being
somewhat quicker, as they are performed in a more contracted scene.
These are the _inimitable_ perfections of a picture, drawn by the rays
of light as the only pencil in nature’s hand, and which are finished
in a moment; for no sensible interval elapses before the painting is
completed, when the ground on which it is painted is prepared and
adjusted. In comparison of such a picture, the finest productions of
the most celebrated artists, the proportions of Raphael, the natural
tints and colouring of Titian, and the shadowing of the Venetians,
are but coarse and sorry daubings, when set in competition with what
nature can exhibit by the rays of light passing through a single lens.
The Camera obscura is at the same time the painter’s assistant, and
the painter’s reproach. From the picture it forms he receives his best
instructions, and is shown what he should endeavour to attain; and
hence, too, he learns the imperfections of his art, and what it is
impossible for him to imitate. As a proof of this, the picture formed
in the dark chamber will bear to be magnified to a great extent,
without defacing its beauty, or injuring the fineness of its parts; but
the finest painted landscape, if viewed through a high magnifier will
appear only as a coarse daubing.
The following scheme will illustrate what has been now stated
respecting the dark chamber. EF represents a darkened room, in the side
of which, IK, is made the circular hole V, in which, on the inside,
is fixed the scioptric ball. At some considerable distance from this
hole is exhibited a landscape of houses, trees, and other objects,
ABCD, which are opposite to the window. The rays which flow from the
different objects which compose this landscape, to the lens at V, and
which pass through it, are converged to their respective foci, on the
opposite wall of the chamber HG or on a white moveable screen placed
in the focus of the lens, where they all combine to paint a lively and
beautiful picture of the range of objects directly opposite, and on
each side, so far as the lens can take in.
Though I have said, that a scioptric ball and socket are expedient to
be used in the above experiment, yet where such an instrument is not
at hand, the lens may be placed in a short tube made of pasteboard or
any other material, and fixed in the hole made in the window shutter.
The only imperfection attending this method is, that the lens can
exhibit those objects only which lie directly opposite the window.
[Illustration: _figure 37._]
Some may be disposed to consider it as an imperfection in this picture,
that all the objects appear in an _inverted_ position; as they must
necessarily do, according to what we formerly stated respecting the
properties of convex lenses, (p. 72). There are, however, different
modes of viewing the picture as if it were erect. For, if we stand
before the picture, and hold a common mirror against our breast at
an acute angle with the picture, and look down upon it, we shall see
all the images of the objects as if restored to their erect position;
and by the reflection of the mirror, the picture will receive such a
lustre as will make it still more delightful. Or, if a large concave
mirror were placed before the picture at such a distance, that its
image may appear before the mirror, it will then appear erect and
pendulous in the air in the front of the mirror. Or, if the image be
received on a frame of paper, we may stand behind the frame, with our
face towards the window, and look down upon the objects, when they will
appear as if erect.
The experiment of the Camera Obscura may serve to explain and
illustrate the nature of a common refracting telescope. Let us suppose,
that the lens in the window-shutter represents the object-glass of a
refracting telescope. This glass forms an image in its focus, which
is in every respect an exact picture or representation of the objects
before it; and consequently the same idea is formed in the mind, of the
nature, form, magnitude, and colour of the object--whether the eye at
the centre of the glass views the object itself, or the image formed in
its focus. For, as formerly stated, the object and its image are both
seen under the same angles by the eye placed at the centre of the lens.
Without such an image as is formed in the camera obscura--depicted
either in the tube of a telescope or in the eye itself--no telescope
could possibly be formed. If we now suppose that, behind the image
formed in the dark chamber, we apply a convex lens of a short focal
distance to view that image, then the image will be seen distinctly,
in the same manner as we view common objects, such as a leaf or a
flower, with a magnifying glass; consequently, the object itself will
be seen distinct and magnified. And, as the same image is nearer to one
lens than the other, it will subtend a larger angle at the nearest
lens, and of course, will appear larger than through the other, and
consequently the object will be seen magnified in proportion. For
example, let us suppose the lens in the camera obscura, or the object
lens of a telescope, to be five feet, or sixty inches focal distance,
at this distance from the glass, an image of the distant objects
opposite to it will be formed. If now, we place a small lens two inches
focal distance beyond this point, or five feet two inches from the
object-glass, the objects, when viewed through the small lens, will
appear considerably magnified, and apparently much nearer than to the
naked eye. The degree of magnifying power is in proportion to the
focal distances of the two glasses; that is, in the present case, in
the proportion of two inches, the focus of the small lens, to sixty
inches, the focus of the object lens. Divide sixty by two, the quotient
is thirty, which gives the magnifying power of such a telescope, that
is, it represents objects thirty times nearer, or under an angle thirty
times larger than to the naked eye. If the eye-glass, instead of being
two inches, were only one and a half inch focus, the magnifying power
would be in the proportion of one and a half to sixty, or forty times.
If the eye-glass were three inches focus, the magnifying power would
be twenty times; and so on, with regard to other proportions. In all
cases, where a telescope is composed of only two convex lenses, the
magnifying power is determined, _by dividing the focal distance of the
object-glass, by the focal distance of the eye-glass_, and the quotient
expresses the number of times the object is magnified, in length
and breadth. This and various other particulars, will be more fully
illustrated in the sequel.
In performing experiments with the camera obscura in a darkened
chamber, it is requisite that the following particulars be attended
to:--1. That the lens be well figured, and free from any veins or
blemishes that might distort the picture. 2. That it be placed
_directly against_ the object whose image we wish to see distinctly
delineated. 3. The lens should be of a proper size both as to its
breadth and focal distance. It should not be less than three or four
feet focal distance, otherwise the picture will be too small, and the
parts of objects too minute to be distinctly perceived; nor should
it exceed fifteen or eighteen feet, as in this case the picture will
be faint, and of course not so pleasing. The best medium as to focal
distance, is from five to eight or ten feet. The aperture, too, or
breadth of the glass, should not be too small, otherwise the image
will be obscure, and the minute parts of it invisible for want of a
sufficient quantity of light. A lens of six feet focal distance, for
example, will require an aperture of at least two inches. Lenses of a
shorter focal distance require less apertures, and those of a longer
focal distance larger. But if the aperture be too large, the image
will be confused, and indistinct, by the admission of too much light.
4. We should never attempt to exhibit the images of objects, unless
when the sun is shining and strongly illuminating the objects, except
in the case of very near objects placed in a good light. As one of the
greatest beauties, in the phenomena of the dark chamber, consists in
the exquisite appearance and contrast of light and shadows, nothing of
this kind can be perceived but from objects directly illuminated by the
sun. 5. A south window should never be used in the forenoon, as the sun
cannot then enlighten the north side of an object; and besides, his
rays would be apt to shine upon the lens, which would make the picture
appear with a confused lustre. An east window is best in the afternoon,
and a western in the morning; but a north window is in most cases to
be preferred, especially in the forenoon, when the sun is shining with
his greatest strength and splendour. In general, that window ought to
be used which looks to the quarter opposite to that in which the sun is
shining.
The picture should be received upon a very white surface, as the finest
and whitest paper, or a painted cloth, bordered with black; as white
bodies reflect most copiously the incident rays, while black surfaces
absorb them. If the screen could be bent into the concave segment of
a sphere, of which the focal distance of the double convex lens which
is used, is the radius, the parts of the picture adjacent to the
extremities would appear most distinct. Sir D. Brewster informs us
that, having tried a number of white substances of different degrees
of smoothness, and several metallic surfaces, on which to receive the
image, he happened to receive the picture on the silvered back of a
looking-glass, and was surprised at the brilliancy and distinctness
with which external objects were represented. To remove the spherical
protuberances of the tin foil, he ground the surface very carefully
with a bed of hones which he had used for working the plane specula of
Newtonian telescopes. By this operation, which may be performed without
injuring the other side of the mirror, he obtained a surface finely
adapted for the reception of images. The minute parts of the landscape
were formed with so much precision, and the brilliancy of colouring
was so uncommonly fine, as to equal, if not exceed the images that are
formed in the air by means of concave specula.
The following additional circumstances may be stated respecting the
phenomena exhibited in the dark chamber. A more critical idea may
be formed of any _movement_ in the picture here presented than from
observing the motion of the object itself. For instance, a man walking
in a picture appears to have an undulating motion, or to rise up and
down every step he takes, and the hands seem to move almost exactly
like a pendulum; whereas scarcely any thing of this kind is observed
in the man himself, as viewed by the naked eye. Again, if an object be
placed just twice the focal distance from the lens without the room,
the image will be formed at the same distance from the lens within the
room, and consequently will be equal in magnitude to the object itself.
The recognition of this principle may be of use to those concerned in
drawing, and who may wish, at any time, to form a picture of the exact
size of the object. If the object be placed further from the lens than
twice its focal length, the image will be less than the object. If it
be placed nearer, the image will be greater than the life. In regard to
immoveable objects, such as houses, gardens, trees, &c., we may form
the images of so many different sizes, by means of different lenses,
the shorter focus making the lesser picture, and the longer focal
distance the largest.
The experiments with the camera obscura, may likewise serve to
illustrate the nature of vision, and the functions of the human eye.
The frame or socket of the scioptric ball may represent the _orbit_
of the natural eye. The ball, which turns every way, resembles the
_globe_ of the eye, moveable in its orbit. The hole in the ball may
represent the _pupil_ of the eye; the convex lens corresponds to the
_crystalline humour_, which is shaped like a lens, and contributes
to form the images of objects on the inner part of the eye. The dark
chamber itself, is somewhat similar to the _internal part of the eye_,
which is lined all around, and under the retina, with a membrane,
over which is spread a mucous of a very black colour. The white wall
or frame of white paper to receive the picture of objects, is a fair
representation of the _retina_ of the eye, on which all the images of
external objects are depicted. Such are some of the general points of
resemblance between the apparatus connected with the dark chamber, and
the organ of vision; but the human eye is an organ of such exquisite
construction, and composed of such a number and variety of delicate
parts, that it cannot be adequately represented by any artificial
contrivance.
The darkened chamber is frequently exhibited in a manner somewhat
different from what we have above described, as in the following
scheme, (fig. 38) which is termed the _revolving camera obscura_. In
this construction, KH represents a plane mirror or metallic reflector,
placed at half a right angle to the convex lens HI, by which, rays
proceeding from objects situated in the direction O are reflected to
the lens, which forms an image of the objects on a round white table
at T, around which several spectators may stand, and view the picture,
as delineated on a horizontal plane. The reflector, along with its
case, is capable of being turned round, by means of a simple apparatus
connected with it, so as to take in, in succession, all the objects
which compose the surrounding scene. But as the image here is received
on a flat surface, the rays _fm_, _en_, will have to diverge farther
than the central rays _dc_; and hence the representation of the
object, near the sides, will be somewhat distorted; to remedy which,
the image should be received on a concave surface, as _ab_ or PS. This
is the general plan of those Camera Obscuras, fitted up in large wooden
tents, which are frequently exhibited in our large cities, and removed
occasionally from one town to another. Were an instrument of this
kind fitted up on a _small scale_, a hole might be made in one of the
sides, as at E, where the eye could be applied to view the picture. The
focal distances of the lenses used in large instruments of this kind,
are generally from eight to twelve feet, in which case they produce
a telescopic effect upon distant objects, so as to make them appear
nearer than when viewed with the naked eye.
[Illustration: _figure 38._]
[Illustration: _figure 39._]
The camera obscura is frequently constructed in a _portable form_,
so as to be carried about for the purpose of delineating landscapes.
The following is a brief description of the instrument in this form.
AC is a convex lens placed near the end of a tube or drawer, which is
moveable in the side of a square box, within which is a plane mirror
DE, reclining backward in an angle of forty-five degrees from the
perpendicular _pn_. The pencils of rays flowing from the object OB,
and passing through the convex lens--instead of proceeding forward and
forming the image HI, are reflected upward by the mirror, and meet in
points as FG, at the same distance at which they would have met at H
and I, if they had not been intercepted by the mirror. At FG, the image
of the object OB is received either on a piece of oiled paper, or more
frequently on a plane _unpolished_ glass, placed in the horizontal
situation FG, which receives the images of all objects, opposite to the
lens, and on which, or on an oiled paper placed upon it, their outlines
may be traced by a pencil. The moveable tube on which the lens is
fixed, serves to adjust the focus for near and distant objects, till
their images appear distinctly painted on the horizontal glass at FG.
Above is shown the most common form of the box of this kind of Camera
Obscura. A is the position of the lens, BC, the position of the mirror,
D, the plane unpolished glass on which the images are depicted, GH a
moveable top or screen to prevent the light from injuring the picture,
and EF, the moveable tube.
[Illustration: _figure 40._]
_The Daguerreotype._--An important, and somewhat surprising discovery
has lately been made, in relation to the picture formed by the Camera
Obscura. It is found, that the images formed by this instrument are
capable of being indelibly fixed on certain surfaces previously
prepared for the purpose, so that the picture is rendered permanent.
When a Camera is presented to any object or landscape strongly
illuminated by the sun, and the prepared ground for receiving the
image is adjusted, and a certain time allowed to elapse till the
rays of light produce their due effect, in a few minutes or even
seconds, a picture of the objects opposite to the lens is indelibly
impressed upon the prepared plate, in all the accurate proportions
and perspective, which distinguish the images formed in a dark
chamber--which representations may be hung up in apartments, along
with other paintings and engravings; and will likely retain their
beauty and lustre for many years. These are pictures of nature’s own
workmanship finished in an extremely short space of time, and with the
most exquisite delicacy and accuracy. The effect is evidently owing to
certain chemical properties in the rays of light; and opens a new field
for experiment and investigation to the philosopher. The only defect
in the picture is, that it is not coloured; but, in the progress of
experiments on this subject, it is not unlikely that even this object
may be accomplished, in which case, we should be able to obtain the
most accurate landscapes and representations of all objects, which
can possibly be formed. This art or discovery goes by the name of the
_Daguerreotype_ from M. Daguerre, a Frenchman, who is supposed to have
been the first discoverer, and who received a large premium from the
French government for disclosing the process, and making the discovery
public. Several improvements and modifications, in reference to the
preparation of the plates, have been made since the discovery was first
announced, about the beginning of 1839; and the pictures formed on this
principle, are frequently distinguished by the name of _Photogenic_
drawings; and are now exhibited at most of our public scientific
institutions.
This new science or art, has been distinguished by different names.
It was first called _Photography_, from two Greek words, signifying
_writing by light_: it was afterwards called the art of _Photogenic
Drawing_, or drawing produced by light. M. Daguerre gave it the name
of _Heliography_, or _writing by the sun_, all which appellatives
are derived from the Greek, and are expressive, in some degree, of
the nature of the process. We shall, however, make use of the term
Daguerreotype, derived from the name of the inventor.
As it does not fall within our plan to give any minute descriptions of
the Daguerreotype process, we shall just give a few general hints in
reference to it, referring those who wish for particular details, to
the separate treatises which have been published respecting it. The
first thing necessary to be attended to in this art is, the preparation
of the plate on which the drawing is to be made. The plate consists
of a thin leaf of copper, plated with silver; both metals together,
not being thicker than a card. The object of the copper is simply to
support the silver, which must be the purest that can be procured. But
though the copper should be no thicker than to serve the purpose of
support, it is necessary that it should be so thick as to prevent the
plate from being warped, which would produce a distortion of the images
traced upon it. This plate must be polished;--and for this purpose, the
following articles are required--a phial of olive oil--some very fine
cotton--pumice-powder, ground till it is almost impalpable, and tied up
in a piece of fine muslin, thin enough to let the powder pass through
without touching the plate when the bag is shaken. A little nitric acid
diluted with sixteen times, by measure, its own quantity of water--a
frame of wire on which to place the plate, when being heated--a spirit
lamp to make the plate hot--a small box with inclined sides within, and
having a lid to shut it up close--and a square board large enough to
hold the drawing, and having catches at the side to keep it steady.
To the above prerequisites, a good _Camera Obscura_ is, of course,
essentially necessary. This instrument should be large enough to admit
the plate of the largest drawing intended to be taken. The lens which
forms the image of the object, should, if possible, be _achromatic_,
and of a considerable diameter. In an excellent instrument of this
description, now before me, the lens is an achromatic, about 3 inches
diameter, but capable of being contracted to a smaller aperture. Its
focal distance is about 17 inches; and the box, exclusive of the tube
which contains the lens, is 15 inches long, 13-1/2 inches broad, and
11 inches deep. It forms a beautiful and well-defined picture of every
well-enlightened object to which it is directed.
Before the plate is placed in the camera, there are certain operations
to be performed. 1. The surface of the plate should be made perfectly
smooth, or highly polished. For this purpose, it must be laid flat,
with the silver side upwards, upon several folds of paper for a
bedding; and having been well polished in the usual way, the surface
must be powdered equally and carefully with fine pumice enclosed in
the muslin bag. Then taking a little cotton wool, dipped in olive
oil, it must be rubbed over the plate with rounding strokes, and then
crossing them by others which commence at right angles with the first.
This process must be repeated frequently, changing the cotton, and
renewing the pumice powder every time. A small portion of cotton must
now be moistened with the diluted nitric acid, and applied equally
to the whole surface. The next thing to be done is to make the plate
thoroughly and equally hot, by holding the plate with a pair of
pincers, by the corner, over a charcoal fire, and when the plate is
sufficiently hot, a white coating will be observed on the silver, which
indicates that that part of the operation is finished. An even cold
surface is next wanted, such as a metallic plate cooled almost to the
freezing point by muriate of soda, and to this the heated plate must be
suddenly transferred.
2. The next operation is to give the plate a coating of _Iodine_. This
is accomplished by fixing the plate upon a board, and then putting it
into a box containing a little dish with iodine divided into small
pieces, with its face downward, and supported with small brackets at
the corners. In this position, the plate must remain till it assume
_a full gold colour_, through the condensation of the iodine on its
surface--which process should be conducted in a darkened apartment.
The requisite time for the condensation of the iodine varies from
five minutes to half an hour. When this process is satisfactorily
accomplished, the plate should be immediately fixed in a frame with
catches and bands, and placed in the Camera; and the transference from
one receptacle to another should be made as quickly as possible, and
with only so much light as will enable the operator to see what he is
doing.
3. The next operation is to obtain the drawing. Having placed the
Camera in front of the scene to be represented, and the lens being
adjusted to the proper focus, the ground-glass of the Camera is
withdrawn, and the prepared plate is substituted for it; and the
whole is left till the natural images are drawn by the natural light
from the object. The time necessary to leave the plate for a complete
delineation of the objects, depends upon the intensity of the light.
Objects in the shade will require more time for their delineation
than those in the broad light. The full clear light of the south of
Europe, Spain, Italy, and particularly, the more glowing brilliancy
of tropical countries, will effect the object much more speedily than
the duller luminosity of a northern clime. Some hours of the day are
likewise more favourable than others. Daguerre states, that ‘the most
favourable, is from 7 A.M. to 3 o’clock P.M., and
that a drawing could be effected in Paris in 3 or 4 minutes, in June
and July, which would require 5 or 6, in May and August, and 7 or 8 in
April and September.’ In the progress of this art, at the present time,
portraits and other objects are frequently delineated in the course of
a few seconds.
4. Immediately after removing the plate from the Camera, it is next
placed over the vapour of mercury, which is placed in a cup at the
bottom of a box, and a spirit lamp applied to its bottom, till the
temperature rise to 140 of Fahrenheit. This process is intended to
bring out the image, which is not visible when withdrawn from the
Camera; but in the course of a few minutes a faint tracery will
begin to appear, and in a very short time the figure will be clearly
developed.
5. The next operation is _to fix the impression_. In order to this, the
coating on which the design was impressed must be removed, to preserve
it from being decomposed by the rays of light. For this purpose, the
plate is placed in a trough containing common water, plunging, and
withdrawing it immediately, and then plunging it into a solution of
salt and water, till the yellow coating has disappeared.
Such is a very brief sketch of the _photogenic_ processes of Daguerre.
Other substances, however, more easily prepared, have been recommended
by Mr. Talbot, F.R.S., who appears, about the same time, to have
invented a process somewhat similar to that of Daguerre. The following
are his directions for the preparation of _Photogenic Paper_.
The paper is to be dipped into a solution of salt in water, in the
proportion of half an ounce of salt to half a pint of water. Let
the superfluous moisture drain off, and then, laying the paper upon
a clean cloth, _dab_ it gently with a napkin, so as to prevent the
salt collecting in one spot more than another. The paper is then to
be pinned down by two of its corners on a drawing board, by means
of common pins, and one side washed or wetted with the Photogenic
fluid, using the brush prepared for that purpose, and taking care to
distribute it equally. Next dry the paper as rapidly as you can at
the fire, and it will be fit for use for most purposes. If, when the
paper is exposed to the sun’s rays, it should assume an irregular tint,
a very thin extra wash of the fluid will render the colour uniform,
and at the same time somewhat darker. Should it be required to make a
more sensitive description of paper, after the first application of
the fluid, the solution of salt should be applied, and the paper dried
at the fire. Apply a second wash of the fluid, and dry it at the fire
again: employ the salt a third time, dry it,--and one application more
of the fluid will, when dried, have made the paper extremely sensitive.
When slips of such papers, differently prepared, are exposed to the
action of day light, those which are soonest affected by the light, by
becoming dark, are the best prepared.
When photogenic drawings are finished in a perfect way, the designs
then taken on the plate or paper are exceedingly beautiful and
correct, and will bear to be inspected with a considerable magnifying
power, so that the most minute portions of the objects delineated may
be distinctly perceived. We have seen portraits, finished in this way
by a London artist, with an accuracy which the best miniature painter
could never attempt--every feature being so distinct, as to bear being
viewed with a deep magnifier. And in landscapes and buildings, such
is the delicacy and accuracy of such representations, that the marks
of the chisel and the crevices in the stones may frequently be seen
by applying a magnifying lens to the picture; so that we may justly
exclaim, in the words of the Poet: ‘Who can paint like nature!.’ That
LIGHT--which is the first-born of Deity, which pervades all
space, and illuminates all worlds--in the twinkling of an eye, and with
an accuracy which no art can imitate, depicts every object in its exact
form and proportions, superior to every thing that human genius can
produce.
The Photogenic art, in its progress, will doubtless be productive of
many highly interesting and beneficial effects. It affords us the power
of representing, by an accurate and rapid process, all the grand and
beautiful objects connected with our globe--the landscapes peculiar
to every country--the lofty ranges of mountains which distinguish
Alpine regions--the noble edifices which art has reared--the monumental
remains of antiquity--and every other object which it would be
interesting for human beings to contemplate; so that in the course
of time, the general scenery of our world, in its prominent parts,
might be exhibited to almost every eye. The commission of the French
Chambers, when referring to this art, has the following remark, ‘To
copy the millions upon millions of hieroglyphics which cover even
the exterior of the great monuments of Thebes and Memphis, of Carnac,
&c., would require scores of years and legions of designers. By the
assistance of the Daguerreotype, a single man could finish that immense
work.’--This instrument lays down objects, which the visual organs
of man would overlook, or might be unable to perceive, with the same
minuteness and nicety, that it delineates the most prominent features
of a landscape. The time-stained excrescences on a tree, the blades
of grass, the leaf of a rose, the neglected weed, the moss on the
summit of a lofty tower, and similar objects, are traced with the same
accuracy as the larger objects in the surrounding scene.
It is not improbable, likewise, that this art (still in its
infancy) when it approximates to perfection, may enable us to take
representations of the sublime objects in the heavens. The sun affords
sufficient light for this purpose; and there appears no insurmountable
obstacle in taking, in this way, a highly magnified picture of that
luminary, which shall be capable of being again magnified by a powerful
microscope. It is by no means improbable, from experiments that have
hitherto been made, that we may obtain an accurate delineation of
the lunar world from the moon herself. The plated disks prepared by
Daguerre receive impressions from the action of the lunar rays to such
an extent as permits the hope that photographic charts of the moon
may soon be obtained; and, if so, they will excel in accuracy all the
delineations of this orb that have hitherto been obtained; and if they
should bear a microscopic power, objects may be perceived on the lunar
surface which have hitherto been invisible. Nor is it impossible that
the planets Venus, Mars, Jupiter and Saturn, may be delineated in
this way, and objects discovered which cannot be descried by means of
the telescope. It might perhaps be considered as beyond the bounds of
probability to expect that even distant _Nebulæ_, might thus be fixed,
and a delineation of their objects produced which shall be capable of
being magnified by microscopes. But we ought to consider that the art
is yet only in its infancy--that plates of a more delicate nature than
those hitherto used, may yet be prepared, and that other properties of
light may yet be discovered, which shall facilitate such designs. For,
we ought now to set no boundaries to the discoveries of science, and to
the practical applications of scientific discovery which genius and art
may accomplish.
In short, this invention leads to the conclusion, that we have
not yet discovered all the wonderful properties of that Luminous
Agent which pervades the universe, and which unveils to us its
beauties and sublimities--and that thousands of admirable objects
and agencies may yet be disclosed to our view through the medium of
light, as philosophical investigators advance in their researches
and discoveries. In the present instance, as well as in many others,
it evidently appears, that the Creator intends, in the course of his
providence, by means of scientific researches, gradually to open to the
view of the inhabitants of our world the wonders, the beauties and the
sublimities of his vast creation, to manifest his infinite wisdom, and
his superabundant goodness, and to raise our souls to the contemplation
and the love of Him who is the original source of all that is glorious
and beneficent in the scene of nature.